The present invention relates to a device and to a method for simulating a sound timbre of a stringed musical instrument. In particular, although not exclusively, the present invention relates to the simulation of a sound timbre belonging to a first electrical stringed musical instrument through the use of a second electrical stringed musical instrument.
Timbre is one of the acoustic-perceptive qualities of a sound, and specifically it is the quality that enables a listener to distinguish that sound from another. Two sounds that are formally identical in terms of tonal pitch, intensity and duration, can in fact be perceived with different timbre when they are emitted by different sound sources.
In musical acoustics, each instrument has its own timbre: the same note played on a violin or on a clarinet can be distinguished immediately. The difference, in acoustic terms, is given by the wave form, which is the resultant of the sum of all the components of the complex signal. A different composition of the signal determines the perception of a different timbre.
Pitches, intensities and durations are qualities of the sound that can be quantified and ordered along a scale, in that they are objective physical values that can be measured respectively with frequency meters, chronometers and sound-level meters. By contrast, the timbre cannot be either quantified or measured, since it is a multidimensional value.
In terms of physics, timbre is explained by the fact that a sound, produced in any way, is never pure, i.e. it can never be represented with a sine curve, but it is instead made up of multiple vibrations called harmonics. In other words a note emitted by a musical instrument has a fundamental frequency, but several others are added to this. Methods are known that make it possible to identify which other frequencies, in addition to the fundamental frequency, make up a note played on a certain instrument. These methods identify the “spectrum” of a note, i.e. the frequency distribution of the sounds of that note.
The presence of harmonics in the spectrum of a note makes it possible to distinguish one instrument from another, or to recognize a same note played in different positions on a same instrument. For example, on a guitar a B played on the free string is perceived differently to a B played on the third string.
Nowadays various techniques and technologies are known which can be used to modify the sound timbre of an electrical musical instrument of the stringed type or even of another type.
Such known technologies are usually implemented inside devices that are commonly used in combination with an electrical stringed musical instrument, such as for example amplifiers or pedal boards, or they are implemented directly in the electrical stringed musical instrument, be it a guitar, a bass guitar or a bowed instrument such as a violin.
With particular reference to electric guitars, these known devices generally use the functionality offered by a hexaphonic guitar pickup, located at the bridge of the guitar in addition to the monophonic pickups. Note that hexaphonic pickups are located at the bridge of the guitar because they start from a sound that is rich in harmonics, i.e. from a standard reference sound.
Devices are known for modifying the sound timbre of an electrical musical instrument, which are adapted to mathematically model the distance of the pickups, whether they are monophonic or hexaphonic, from the bridge of the instrument, such modeling taking place in the time domain, in particular by acting on delays.
However, such type of known devices is based on a rather limiting assumption, i.e. that the sound timbre of a musical instrument depends exclusively on the position of the hexaphonic pickup.
Further devices are known for modifying the sound timbre of an electrical musical instrument which complement the mathematical modeling by also analyzing the distance from the strings and from the microphone, in addition to the previously-mentioned distance of the pickups, both monophonic and hexaphonic, from the bridge of the instrument.
Finally, further devices are known for modifying the sound timbre of an electrical musical instrument which, in addition to mathematically modeling the distance of the pickups, both monophonic and hexaphonic, from the bridge of the instrument, and optionally the distance from the strings and from the microphone, apply DSP (Digital Signal Processing) solutions which are integrated in the electrical stringed musical instrument proper.
All these known devices make it possible, starting from the vibration of the strings of a stringed instrument, in particular of an electric guitar, to process the signal induced by that vibration in order to make it audible using an amplifier or a loudspeaker.
The variety of stringed musical instruments known today is such that, in particular among music amateurs and experts, one type of musical instrument can be immediately distinguished from another. For example, a Fender Stratocaster guitar, used to play a song, will give a different result from a Gibson Les Paul.
Usually, the sound timbre is influenced by a plurality of factors. A first factor is constituted for example by the characteristics of the musical instrument played, such as the shape of the harmonic body, the type of wood, the type of pickup used, for example single coil or humbucking, and the position of the pickup, for example in the bridge or in the neck. A second factor is determined by the characteristics of the strings used, which differ in terms of quality, thickness, and state of wear. Other factors are ascribable to the adjustment of the tone and volume knobs, or to the player's technique, which can vary for example according to the shape and thickness of the plectrum, the intensity of the picking, the use of pizzicato techniques with the fingernails or with the fingertips, use of an e-bow, and so on.
EPA 2,372,692 describes a technology for imparting the resonance effect of an acoustic stringed musical instrument to an amplified audio signal, acoustic resonance being a typical characteristic of the acquisition or registration of sound by way of a microphone.
The aim of the present invention is to overcome the above mentioned drawbacks of the known art, by devising a device and a method for simulating a sound timbre, particularly for stringed electrical musical instruments, which make it possible to obtain effects similar to the effects that can be obtained with known solutions, by making it possible to modify the sound timbre of a first electrical stringed musical instrument, herein referred to as the source instrument, until it is made wholly identical to the sound timbre of a second stringed musical instrument, herein referred to as the target instrument.